A multicolor paint is a composition which, when coated on a surface and dried, results in a coating that is characterized by dispersed discrete visibly discernible spots (or dots).
Water-in-water multicolor paints have been proposed (see, for example, Sellars et al. U.S. Pat. No. 3,950,283; Grasko U.S. Pat. No. 3,852,076 and Zola U.S. Pat. No. 4,376,654) and are of commercial interest particularly in view of the developing governmental interest in establishing regulations limiting the quantity of organic volatiles emitted into the environment by a paint during application and subsequent air drying. The states of California, New Jersey and New York, for example, have adopted regulations limiting paint emissions and many other states reportedly will be adopting similar regulations.
The above-indicated related applications and patents provide new and very useful water-in-water multicolor paints which overcome various prior art problems. In such a new multicolor paint, there are aqueous disperse phase color bodies that are characterized by having:
(a) a relatively high content of water dispersible, film-forming, crosslinkable polymer in association with a crosslinking agent, PA1 (b) a relatively high structural integrity, and PA1 (c) a capacity to form highly crosslinked, water insoluble, chemical resistant, mar resistant and thermally stable coatings with a high degree of hardness after paint application and drying. PA1 (a) water dispersed, inert film-forming, crosslinkable polyurethane polymer system selected from the group consisting of a polyurethane polymer system, a carboxylated polymer system, and mixtures thereof, and PA1 (b) hydroxy (lower alkyl) cellulose and/or alkali metal carboxyl (lower alkyl) cellulose.
These water-in-water multicolor paints are based upon crosslinkable carboxylated polymers and crosslinkable polyurethane polymers.
When a painter manually applies such a water-based multicolor paint emulsion by transfer from an applicator (such as a brush, roller or the like), there is a tendency for the painter to stroke the paint-carrying applicator backwards and forwards repetitively over the substrate being coated (i.e., painted) in order to achieve the desired transfer and coverage (with regard to both initial paint application and also paint coating thickness). The more the stroking, the greater the possibility of rupturing a portion of some of the disperse phase bodies that produce the multicolor effect in a dried coated paint. To minimize the possibility of such undesirable rupturing, it would be desirable to somehow effectuate a more rapid transfer of multicolor paint from an applicator to a substrate. Associated further properties of early tack, quick stick and significant green strength would also be desirable.
The present invention provides a multicolor paint emulsion which provides such an accelerated paint transfer capability.